In order to render the seats of motor vehicles comfortable, it is known to provide a lumbar support, i.e., a device placed within the backrest and comprising a resting element that is coupled to a frame of the backrest and that defines a shaped front surface placed at the height of the lumbosacral area of the body of the person occupying the seat. In general, the lumbar support also comprises an adjustment device, which is actuatable by the user for adapting the shape and/or position of the resting element according to the anatomical conformation of his own body and/or to requirements of personal comfort.
There is then known the tendency to provide lumbar supports that contribute to the safety of the person occupying the seat in the case of an accident with rear impact against the motor vehicle. This type of lumbar supports comprises a resting element that is able to undergo displacement backwards in the case of an accident with rear impact so as to allow the body of the user to approach the headrest of the seat in order to limit the so-called “whiplash” phenomenon. In this context, there is a long felt unmet need to provide a lumbar support that will be extremely simple and will have a small number of components.